Characteristics of living things

 Living organisms have their own characteristics. On the basis of certain characteristics, living organisms can be distinguished from non-living like stone, car, pencil, table, etc. The living organisms have
The following characteristics which are not found in non living organisms.
1. Definite shape and size
2. Cellular structure and protoplasm
3. Movement and locomotion
4. Nutrition
5. Respiration
6. Metabolism
7. Excretion
8. Irritability
9. Reproduction
10. Growth
11. Life-cycle
12. Repair of injured part
13. Ageing and death

1. Definite shape and size: All living organisms have definite shape and size. Due to this shape and size, we can distinguish them from one to another. Non-living has
No definite shape or size. For example, stone, sand, water, and a piece of wood have no definite shape and size.

2. Cellular structure and protoplasm: All living beings are made up of small unit called cell. Each cell is the structural and fictional unit of the body containing protoplasm which performs all the functions of the
Body. Hence, protoplasm is called the physical basis of life.

3. Movement and locomotion: Movement is the process in which the entire body moves from one place to another. Generally locomotion is commonly seen in animals. Animals generally move from one place to another by locomotory
Organs. Amoeba moves by pseudopodium, paramecium by cilia, insects by wings and man by legs.
Movement of plants is generally due to external stimuli and shows slow movement. Plants are fixed to the soil so they cannot move.
The bending of plants towards light is also a kind of movement.

4. Nutrition: Every living organism requires food for energy to perform various body functions. Nutrition is a process of taking food. Plants are autotrophs as they can synthesize food their own photosynthesis. Animals are
Heterotrophs as they are dependent on others for foods. Non-living has not such type or nutrition.

5. Respiration: All living things (plants and animals) perform respiration. In this process oxygen is taken in to oxidize the foods in order to release energy. Carbon dioxide and oxygen are released as by products. To carry out
This process, various respiratory organs are found in living organisms. A non-living cannot perform respiration

6. Metabolism: Various physiological activities are going inside the body of living organisms. All these physiological activities together called as metabolism. It can be divided in two parts
(I) Anabolism
(ii) Catabolism
Anabolism is a constructive process. One of such processes is photosynthesis. In this process, glucose in synthesized.
Catabolism is a destructive process. In this process substances are broken down. One of such processes is glucose is broken down into water, carbon dioxide and energy.

7. Excretion: Excretion means discharge of metabolic wastes. Due to metabolic processes inside the body, many excretory products like carbon dioxide, water, inorganic salts, urea, uric acid, creatinine, etc. are formed. As these
Substances are very toxic, therefore, they are urgently required to expel out from the body. The removal of these waste substances is called excretion.

8. Irritability: It is the ability of organism to respond to the stimuli. Any change in the environment is called the stimulus and the response of the organism though the stimulus is due to irritability. The movement of plant towards
Light, contraction and expansion of pupil due to change in the intensity of light, etc. are the examples of sensitivity or irritability.

9. Reproduction: Living organisms have the ability to produce young ones. The process of giving birth to the young ones of its own kind is called reproduction. Lower organisms reproduce asexually whereas the higher organisms reproduce
Sexually. Reproduction is essential (I) to increase the number of its own kind and (ii) for continuation of race of the organism. But non living things like stone or a chair cannot reproduce its own kind.

10. Growth: Growth is increase in size followed by permanent change in its form. Living organisms as a result of building up of protoplasm within the cells and this is due to intrinsic (internal) growth of organism. In non-living increase
In size may take place but this is due to deposition of materials on its outer surface (extrinsic).

11. Life-cycle: During development an animal or a plant passes through different stages before attaining an adult individual. In any living organism these stages are passed in a cycle and so the different stages of the developing individual
From the formation of zygote up to the adult stage is called is life-cycle. This is characteristic of higher living organisms and is absent in non-living.

12. Repair of injured part: living body can repair an injured part but non living cannot do so. For example, if small part of a stone is broken it cannot repair the broken end.

13. Ageing and death: Every living organism has a definite life span. At the end, it dies. This is applicable to both plants and animals. But a piece of stone can stay on the earth for a definite time. It has no definite age when it dies.